③-How did you do in the test?

　　-Not so well. I could have done much better but I misread the directions.

　　④The streets are wet. It must have rained last night.

　　(2)完成句子

　　①你不可能买一辆这么昂贵的车。你肯定是从一个富朋友那里借的。

　　You couldn't_have_bought such an expensive car.You must_have_borrowed it from a rich friend.

　　②我本来可以帮助你的，但那时我太忙了。

　　I could_have_helped_you，but I was too busy then.

　　③灯还亮着，所以他不可能出去了。

　　The light in his room is still on, so he can't_have_gone_out.

　　④我房间里的手机找不到了。有可能被我姐姐拿走了。

　　I can't find my mobile phone in my room.It might/may_have_been_taken_away by my elder sister.

　　4．ought to/should have done 表示过去本来应该做某事(而实际上并没有做)，意为"理应做......，本来应该做......"，常表示遗憾；ought not to/shouldn't have done 表示"过去本来不应该做某事(而实际上做了)"，含有指责对方或自责的意味。

　　The flowers have died. I should have watered them often.

　　这些花儿都死了。我本来应该常给它们浇水的。(其实没浇水，表示遗憾)

　　You ought not to have told them the truth.

　　你本不应该告诉他们真相的。(其实你告诉他们了，含有责备的意味)

　　5．needn't have done sth.表示"本来不必做某事(实际上已经做了)"； need have done sth.表示"本来需要做某事(实际上未做)"

　　I needn't have bought so much wine - only five people came.

　　我本来没有必要买这么多酒，只来了五个人。

　　He need have hurried to the station. In that case, he wouldn't have missed the train.

　　他本来需要快点去车站。那样的话，他就不会误了火车。

　　6．would have done sth.表示"原本想做某事"；也可以用于虚拟语气中，表示与过去事实相反。

　　I would have given you the book yesterday，but I didn't cover it completely.

　　我原本想昨天给你那本书的，可是我没能全部读完。

　　It would never have happened without your help.

　　要不是你的帮助，这绝不会发生。

[即时演练2]